Yes, the tankless water heaters do cost more than the normal water heaters because tankless water heaters are designed to supply hot water only when needed unlike normal ones.
American Water Heaters.
Electric water heaters have not carbon monoxide.
American Water Heaters
Some of the water heaters uses magnets. Magnets softens the water.
GE hot water heaters are made by Rheem.
Rheem or Ruud. G.E. water heaters are made by them also.
You can buy water heaters from any home hardware store.
Rheem provide a series of high efficiency gas water heaters. Several different companies also provide tank-less water heaters, which are very efficient, as well as solar water heaters.
Water heaters can range from 1 unit to 10 units.
"Rheem does manufacture both gas and electric water heaters. Rheem currently offers 18 different varieties of gas water heaters and 9 different varieties of electric water heaters. Both types of Rheem water heaters are known for their rigorous standards, reliability, and efficiency."
Titan tankless water heaters can be purchased online at Tank the Tank, Hot Water, Local, Amazon, eBay, Titan, Titan Water Heaters, and Tankless Water Heaters.